Distributor phase corrector circuit



March 22, 1949.

Filed Nov. 30, 1945 3 Q m xv xqmm \d L Q jii m-U p H F L. t X m E I N 3v wvmmvu w UM .wm m EGR 3 it is necessary to correct the speed or phase of Patented Mar. 22, 1949 UNITED STATES PATENT OFFICE DISTRIBUTOR PHASE CORRECTOR CIRCUIT Warren A. Anderson, West Brighton, Staten Island, N. Y., assignor to Radio Corporation of America, a corporation of Delaware Application November 30, 1945, Serial No. 632,041

7 Claims. (Cl. 178-53) 1 2 This invention relates to a phase corrector such a capacitor 12 and a resistor 2 to ground. When as may be employed, for example, in maintaining the tongue ll rests upon the marking contact m synchronism between two rotating members, at the capacitor receives a negative charge from a the transmitter and receiver respectively, in a direct current source the negative terminal of synchronous telegraph system. The rotating which is indicated at I3, and the positive terminal members may be distributor brushes, or cams for of which will be understood to be grounded. cyclic circuit closing operations, or rotatable reac- When the tongue ll rests upon its spacing contors such as disclosed in U. S. Patent 2,275,974 tact s the capacitor I2 is discharged through a which issued March 10, 1942 to Richard E. resistor l4. Mathes. Other uses, however, will suggest themw The distributor ill, Whose brushes are to be selves to those skilled in the art. phase-corrected, is indicated in developed form.

In multiplex telegraph and analogous systems, This distributor comprises conventionally a slip ring 4!, a segmented ring 42, and these two rings the distributor or other periodic device in order being swept by one pair of interconnected brushes to correctly translate the code elements of an 15 46 and H. The distributor also includes a slip incoming train of telegraph signals. There are ring 43 and a segmented ring 44 which are swept numerous known systems of phase or speed corover by a pair of interconnected brushes 48 and 49 rection, some of which operate, as in the instant respectively. The segments of ring 44 are used case, to accelerate or retard the shaft of a driving for translation of the incoming signals by conmotor and the rotating member coupled thereto ventional receiving telegraph instrumentalities. whenever the angular displacement of a rotor The junction between one terminal of conrequires re:toration to proper phase. I have denser l2 and interconnected terminals of the found, however, that the phase corrector circuit resistors l4 and 2 is connected to the slip ring arrangement of my invention overcomes an infor purposes of actuating the phase correcting herent disadvantage of hitherto known systemsin system of my nve r a e S e s a that a, tendency to produce over-correction is in the ring 42 are interconnected and are also avoided. connected to the control grid in a gating tube 3 It is an object of my invention to provide means Which m y b of the triode yp if desiredof extremely simple construction for correcting ments b Which intervene between S e s a phase difierences between two rotating members may, to all intents and purposes, be regarded usually located at stations remote from each as insulation segm The se ents a are in other, where phase correction is accomplished by radial alignment With active Segments 0 n e referring the local control of one rotating member signal r n 44- m nts a and 0 each extend to the received intelligence signal elements. v r n arc sufiicient 0 p kp pproximately Another object of my invention is to provide 5 alf of a signal of dot unit len accurate phase correction of a receiving dis- The control grid in tube 3 is connected to tributor brush or other rotatable member with ground through a resistor l5 and is also connected respect to the incoming periodicity of incoming through a resistor ll to the positive terminal of signals in such manner as to avoid over-correction a direct current source as indicated by the sign in the event of signal distortion. at It, this source having its negative terminal Other objects and advantages of my invention grounded. The anode in tube 3 is connected to will be made apparent in the detailed description the positive terminal of source l6 through a to follow. This description is accompanied by a resistor l. The cathode of the same tube is drawing the sole figure of which shows diagramgrounded, as is the negative terminalof source It. matically a preferred embodiment of the invention. time constant circuit connected across the tertransmitted from a distant point arrive over a line ranged to be charged when tube 3 is non-conduc- L and pass through the coil of relay I to ground. tive and to be discharged when tube 3 becomes It-may be considered, for example, that the signals 50 conductive. The purpose of this time constant are of the plus-and-minus type and accordingly will be explained hereinafter.

relay I is a polar relay, though, of course, it may A conventional flip-flop circuit 8 is shown havbe a simple relay where on-and-ofi signals are ing two triode discharge devices It and I9 and used. associated circuit parameters including anode Thetcngue ll of relay I is connected through resistors 20, grid resistors 2|, and a control circuit A capacitor 6, together with resistor 1, form a Referring to the drawing, the incoming signals minals of the source l6. Capacitor 6 is thus arfor tube I 8 which includes a resistor 22 in series with a coupling capacitor 23 across which pulses are fed to tube l8 from the junction between resistor l and capacitor 6. The flip-flop circuit is also provided with cross-coupling connections between the anode of each tube and the grid of the other tube, one of these cross-connections being through a resistor 24 while the other includes a coupling capacitor 25.

The flip-flop circuit has a stable state in which tube I8 is normally non-conducting and tube 19. is normally conducting. In the active or tripped (sometimes called the unstable) state, resulting from a tripping pulse, the tube I8 is conducting and the tube [9 is non-conducting. After a period of time in the active state, depending upon' the time constants of the flip-flop circuit, this circuit will restore itzelf to the stable state.

A utilization circuit is connected to the output side of the flip-flop circuit arrangement 8 and includes a relay tube 9 whose cathode is grounded, whose grid is normally negatively biased by a connection through resistor 26 to the negative source I 3, and whose anode is connected to the positive terminal of source It through the winding of a magnet I [I which controls the mechanism of the phase corrector. The anode of tube [9, and the grid of tube 9 are coupled together through a resistor 21 of relatively high ohmic value.

In the operation of my improved phase corrector circuit arrangement negative pulses produced across resistor 2 at the start of each mark. signal are coupled to the grid of the gating tube 3 through the correction segments a of the distributor ring 42. The duration of the pulse coupled to the grid of triode 3 is dependent on the phase of the brush 4 at the start of mark with respect to the segments.

It will be noted that a positive bias is normally applied to the grid of tube 3 so that this tube stands ina conductive state except when a negative pulse is applied through the distributor.

state of tube 3 condenser E charges through resistor 'l'from the plus voltage of the source I6.- The product of ohmic value of resistor 7 and the capacitive value of condenser 6 is made sufiiciently large so that the voltage to whiclrcondenser 6 can charge (in the maximum time available) is directly proportional to time. When the pulse from the distributor ends triode 3-again becomes conductive and discharges the condenser 6 with the result that a saw-tooth wave is developed across capacitor 23 for controlling the flip-flop circuit 8.

The coupling impedance between the anode of tube 3 and the grid of tube I8 is suitably chosen to avoid unbalancing of the circuitparameters in the flip-flop circuit. The flip-flop circuit as a whole behava like a quick-acting,

slow release relay and times the length of the.

pulses which pass through the amplifier tube 9 and through the corrector actuator magnet l0.

However, the saw-tooth wave peak applied to the grid of tube I8 must be of a predetermined minimum amplitude, as provided by the charge on condenser 6 in order to trigger the tube into the active state. phase departure is essential for starting ofthe flip-flop action.

Since the flip-flop circuit 8 becomes insensitive to external control until tube I8 is again blocked, the release time of this circuit will be.

This negative pulse operates to bias the, tube 3 to cut-off. During the non-conductive Thus a predetermined minimum" adjusted to avoid overcompensation in the phase correction function. This is accomplished by a choice of values of the components 2| and so as to limit the number of correction impulses which may be applied during any given period.

I have not shown the means for applying the efiects of operating the release magnet [0 for re-orientation of the distributor brushes since it will be well understood by those skilled in the art that conventional means may be employed. For example, if the distributor motor speed at the, receivin station is adjusted for a normal gain over the speed of the distributor motor speed at the. transmitting station, then phase correction is conventionally obtained by any suitable stepwise-operated mechanism to rethe stable state to the; active orient the receiver brushes backward independently of the driving motor whenever the magnet H1 is energized. If the receiving distributor speed normally produces a lag in its phase, then the phase corrector can be arranged to. re-orient the brushes in a forward. direction.

As shown in Patent- 2,038,375, granted- Apri1 21', 1936'to R. E. Mathes, the phase corrector mechanism may take the form of an auxiliarymotor geared to an orientable stator housing for the. distributor driving motor. In such av case my. actuator magnet in would possess contacts 511; for, closing a circuit through the windings of the auxiliary corrector motor. Other mechanisms. for reorientation of the brushes or equivalentroetatable members are also known in the art.

Various modifications of my invention may be. made without departing from its spirit andscope. The embodiment shown is merely illustrative.

I claim:

1. A device for use in correcting the phasaot" a rotatable member to maintain it in synchroa. nism with theperiodicity of an incoming trainzof; code signals, comprising a circuit arrangement; for. producing a pulse whichcorresponds with. the start-of-mark in said signals, a flip-flop-ciry. cuit including twodischarge tubes eachsubiect: to control throughits input circuit and each have. ing its input circuit coupled to the output Gil-a cuit of the other for producing mutual inter,-. action, means operative under normal conditions. to hold the first of saidtubes non-conductive; and the second of said tubes conductive, meansde-H pendent upon departures of said rotatable memher from proper phaserelationtosaid signals 1 for producingand feeding-a saw-tootnwaveto, the input circuit of theiirsttube, thereby-jo n block the same, and timeconstant elements-im, cluded as. components of; said, flip-flop circuit,

said elements constituting means for rendering saidflip-flop circuit insensitive to further-cen trol by said saw-tooth'wave during.- a predeter mined time interval.

In oniz ne r t mi nq tinu rslxv rotatable member the. phase of which is to be corrected relative to the cadence of an incom ingtrain of code signals, magnetic means for controlling the times of necessary phase .corneotion;v of said member meansincluding a alt-restoring; trigger circuit having two cross-coupled discharge: devices for causingalternateaction and inaction of i magnetic m anst eid fi i er mi i 'have e a bl state anden cfiv -s jateanda ay ns. the Operational he te ist q .pt guiqkw me slow-release, relay pulses and easem nt upb 'departures of said; rotatable member from-proper phase relation said signals for tripping said trigger circuit from;

tat he y-w r ei m ansresn nsi a a.

operate said magnetic means, and a capacitor feeding pulses to said tripping circuit means, said capacitor being arranged to receive a charge at the start of mark and to dissipate said charge at the end of mark in said train of code signals.

3. The combination according to claim 2 and including a distributor having corrector segments and a brush rotatable with said rotatable member, said circuit means having connections for feeding pulses through said brush and corrector segments to said trigger circuit for tripping the same.

4. In a phase corrector for a cyclically operable unit in a multiplex telegraph system, a phase correcting circuit operable under coordinated control of a train of incoming code signals and a circuit interruptor which constitutes a part of said unit, said correcting circuit comprising a capacitor which is chargeable upon signal transition from space to mark and dischargeable upon signal transition from mark to space, a signal-controlled relay and resistive means connected to a direct current source for causing said capacitor to be alternately charged and discharged, an electronic trigger circuit having the operational characteristics of a quick-acting slow-release relay and having an input control circuit coupled through said circuit interrupter to one terminal of said capacitor, and means subject to control by said trigger circuit for effecting re-orie-ntation of said cylindrically operable unit, thereby to restore its proper phase relation to said signals.

5. In a device according to claim 4 in which said trigger circuit includes a pair of discharge devices, a capacitor inter-coupling an input electrode of one discharge device and an output electrode of another discharge device in said trigger circuit, and a resistor interconnecting said input electrode and a cathode in said one device, said capacitor and resistor constituting a time constant circuit for fixing the release-period of said trigger circuit.

6. In a synchronizing system, a source of synchronizing impulses of one polarity, a normally conductive discharge tube having an input circuit subject to control by said impulse-s for biasing the tube to cut-off, a trigger circuit of the type having two cross-coupled discharge devices and having the operational characteristics of a quickacting slow-release relay, a distributor comprising a, brush continuously rotatable over a segmented ring, alternate segments of which are interconnected, a connection between said brush and said source of synchronizing impulses, another connection between said interconnected segments and the input circuit of said normally conductive tube, means for causing that tube when blocked by said impulses conducted through said segments to unblock a normally blocked one of the discharge devices of said trigger circuit, and means coupled to an output electrode in the other of said trigger circuit discharge devices for controlling a re-orientation device by which the phase relation of said distributor to said synchronizing impulses is maintained.

7. A system for maintaining a local device in synchronism with the periodic reception of incoming signal elements, comprising means for producing local pulses of one polarity in response to transitions from spacing to marking characteristics of said elements, a distributor comprising a brush continuously rotatable over a segmented ring, alternate segments of which are interconnected, a connection from said pulse producing means to said brush, a gating discharge tube having input and output circuits the input circuit being connected to said interconnected segments, means operable under control of said pulses when they are permitted to be conducted through said segments for blocking said gating tube, an electronic trigger circuit comprising cross-coupled discharge devices and time constant circuit components whereby quick triggering action and slow recovery to normal are obtained as operational characteristics of the trigger circuit, a connection from an output electrode of said gating tube to an input electrode of one device in said trigger circuit which is normally held non-conductive, and a utilization device coupled to an output electrode of the other device in said trigger circuit, said utilization de- 49 vice being operable to restore a proper phase relation between said brush and the arrival moments of said signal elements.

WARREN A. ANDERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,237,156 Mathes Apr. 1, 1941 2,270,449 Kahn Jan. 20, 1942 

